Evidence of groove damage of TT setup?

Pawlowski,

Here's a foolproof test to determine whether any particular stretch of groove is damaged, flawed or dirty - or not:

1. With the system powered up but the TT motor off, cue the stylus down just before one of the offending passages.

2. Move the platter slowly (always forward!) by hand. The music will make a low frequency growl.

3. If the vinyl has pressing flaws, was damaged by prior abuse or is grundged up with dirt you'll hear it very clearly.

At this slow speed no stylus will mistrack, so if you hear non-musical artifacts you'll know it's something on the record.

Best,
Doug

Doug; I've never encountered that advice before - and I don't get to say that too often - but, look forward to trying it!!

Audiofeil,

I'm guessing I haven't run across too many of YOUR old LPs in the thrift stores... :-)

Dougdeacon,

I tried your slow rotation test on a record that certainly sounds pretty damaged at 33 rpm, and then again on a known clean and undamaged disc, but the "non-musical artifacts" weren't really obvious to me on the damaged record. Can you describe in more detail what you hear using this method?

David

David says:
>>I'm guessing I haven't run across too many of YOUR old LPs in the thrift stores... :-)<<

You have a better chance of winning the lottery.
:-))))))))))))

Have fun!!

David,

The slow rotation test is excellent for detecting pressing voids and sporadic vinyl damage at dynamic peaks due to mistracking cartridges. Those produce sharper-edged shapes in the vinyl than any musical waveform, they're faster than the fastest transient cut by a cutting head. Even at slow rpm's, where musical information all sounds fairly low pitched, flaws and damage like that sound sharp and crisp.

I haven't tried it on a record with general background noise or grunge, so I'm not sure how that would sound. Probably results would vary depending on the shape of the grunge?

Doug